01 March 2005
subjected to vibration and slip. The relative motion
between the two surfaces is extremely small.
Fairing - A shape that produces a smooth transition
Fungus - A group of parasitic lower plants that feed on
from one angular direction to another.
dead or decaying organic matter. Includes molds,
mildews, smuts, mushrooms and some bacteria.
Fatigue - The tendency of a material to fracture under
repeated cyclic stressing.
Faying Surface - The common surface between mating
Galvanic - A chemical reaction involving two dissimilar
Faying Surface Seal - A preassembled seal installed
Galvanic Corrosion - The accelerated corrosion of a
between two mating surfaces, used to prevent corrosion.
metal that is associated with the flow of electrons from
In combination with fillet seals, faying surface seals
a less active metal in the same solution and in contact
prevent a leak path from extending through a faying
with the more active metal.
surface into an interior area.
Galvanic Couple - A closed electric circuit of two
Feathering - To spread out (as paint) especially around
connected dissimilar metals joined by an electrolyte.
the edges of a particular area in order to blend in with
adjoining matter and leave no clear lines of distinction.
Galvanic Series - A list of metals and alloys arranged
in order of their tendency to corrode in a given
Filiform Corrosion - Corrosion that develops under
environment. The galvanic series is a more accurate
coatings on metals, and appears as fine ragged hairlines,
predictor of galvanic relationships than the electromotive
usually wavy or curved and randomly distributed.
force (EMF) series.
Fillet Seal - A primary seal applied at the meeting of two
Gloss - The degree to which a surface reflects light.
adjoining surfaces and along the edges of faying surfaces
Gloss is the opposite of flat.
as a continuous bead after part assembly. It can be
applied over, along the edges, and between mating
Hazardous Material - A material which may pose a
Film - A thin layer of material that may or may not be
threat to human health or the environment when
visible to the eye.
improperly handled or disposed of.
Fish-Eyes - Craters distinguished by a center which
Hazardous Waste - Waste which is characterized by
consists of a uniform flat painted region, surrounded by
the Environmental Protection Agency (EPA) as 1)
a depression, followed by a ridge of paint. Fish-eyes are
ignitable, 2) corrosive, 3) reactive, or 4) toxic, as defined
caused by undispersed fluid globules in the paint or by
in 40 CFR 261, or is a listed hazardous waste identified
airborne droplets that are deposited on the painted
in that regulation.
Flammable Liquid - Any liquid having a flash point of
caused by the absorption of hydrogen ions. Hydrogen
100°F or less.
may be generated as a by-product of corrosion or
through various manufacturing operations (cleaning,
Flashpoint - The minimum temperature at which a
plating). High strength steel alloys are most susceptible
liquid gives off an ignitable vapor.
to hydrogen embrittlement.
Flat - A surface with minimal reflection. Flat is the
Hygroscopic - The property of readily absorbing and
opposite of gloss.
Fretting Corrosion - Corrosion which occurs at the
interface of two mating surfaces, under load and